Deadly Arizona Wildfire Is Just Getting Bigger [PHOTOS]

The fast-moving fire, started by a lightning strike and fueled by dry vegetation, gusty winds, low humidity, and high temperatures, tripled in size in a matter of hours on Sunday, local news station ABC 15 reported.

Hundreds of firefighters are in the area trying to contain the blaze. The wildfire is 0% contained.

Most of Yarnell, Arizona's 700 residents have evacuated the town about 85 miles northwest of Phoenix, according to the Associated Press.

Of the 500 structures in the town, half of them have been destroyed, according to ABC 15. The area hasn't seen a major fire in 40 years.

The firefighters who died were part of an elite crew trained to battle wildfires. The Yarnell fire has been the deadliest U.S. wildfire involving firefighters in the past 30 years at least, the AP reported.